third_party/heimdal/kdc/misc.c

   1 /*
   2  * Copyright (c) 1997 - 2001 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include "kdc_locl.h"
  35
  36 static int
  37 name_type_ok(krb5_context context,
  38              krb5_kdc_configuration *config,
  39              krb5_const_principal principal)
  40 {
  41     int nt = krb5_principal_get_type(context, principal);
  42
  43     if (!krb5_principal_is_krbtgt(context, principal))
  44         return 1;
  45     if (nt == KRB5_NT_SRV_INST || nt == KRB5_NT_UNKNOWN)
  46         return 1;
  47     if (config->strict_nametypes == 0)
  48         return 1;
  49     return 0;
  50 }
  51
  52 struct timeval _kdc_now;
  53
  54 static krb5_error_code
  55 synthesize_hdb_close(krb5_context context, struct HDB *db)
  56 {
  57     (void) context;
  58     (void) db;
  59     return 0;
  60 }
  61
  62 /*
  63  * Synthesize an HDB entry suitable for PKINIT and GSS preauth.
  64  */
  65 static krb5_error_code
  66 synthesize_client(krb5_context context,
  67                   krb5_kdc_configuration *config,
  68                   krb5_const_principal princ,
  69                   HDB **db,
  70                   hdb_entry **h)
  71 {
  72     static HDB null_db;
  73     krb5_error_code ret;
  74     hdb_entry *e;
  75
  76     /* Hope this works! */
  77     null_db.hdb_destroy = synthesize_hdb_close;
  78     null_db.hdb_close = synthesize_hdb_close;
  79     if (db)
  80         *db = &null_db;
  81
  82     ret = (e = calloc(1, sizeof(*e))) ? 0 : krb5_enomem(context);
  83     if (ret == 0) {
  84         e->flags.client = 1;
  85         e->flags.immutable = 1;
  86         e->flags.virtual = 1;
  87         e->flags.synthetic = 1;
  88         e->flags.do_not_store = 1;
  89         e->kvno = 1;
  90         e->keys.len = 0;
  91         e->keys.val = NULL;
  92         e->created_by.time = time(NULL);
  93         e->modified_by = NULL;
  94         e->valid_start = NULL;
  95         e->valid_end = NULL;
  96         e->pw_end = NULL;
  97         e->etypes = NULL;
  98         e->generation = NULL;
  99         e->extensions = NULL;
 100     }
 101     if (ret == 0)
 102         ret = (e->max_renew = calloc(1, sizeof(*e->max_renew))) ?
 103             0 : krb5_enomem(context);
 104     if (ret == 0)
 105         ret = (e->max_life = calloc(1, sizeof(*e->max_life))) ?
 106             0 : krb5_enomem(context);
 107     if (ret == 0)
 108         ret = krb5_copy_principal(context, princ, &e->principal);
 109     if (ret == 0)
 110         ret = krb5_copy_principal(context, princ, &e->created_by.principal);
 111     if (ret == 0) {
 112         /*
 113          * We can't check OCSP in the TGS path, so we can't let tickets for
 114          * synthetic principals live very long.
 115          */
 116         *(e->max_renew) = config->synthetic_clients_max_renew;
 117         *(e->max_life) = config->synthetic_clients_max_life;
 118         *h = e;
 119     } else if (e) {
 120         hdb_free_entry(context, &null_db, e);
 121     }
 122     return ret;
 123 }
 124
 125 KDC_LIB_FUNCTION krb5_error_code KDC_LIB_CALL
 126 _kdc_db_fetch(krb5_context context,
 127               krb5_kdc_configuration *config,
 128               krb5_const_principal principal,
 129               unsigned flags,
 130               krb5uint32 *kvno_ptr,
 131               HDB **db,
 132               hdb_entry **h)
 133 {
 134     hdb_entry *ent = NULL;
 135     krb5_error_code ret = HDB_ERR_NOENTRY;
 136     int i;
 137     unsigned kvno = 0;
 138     krb5_principal enterprise_principal = NULL;
 139     krb5_const_principal princ;
 140
 141     *h = NULL;
 142     if (db)
 143         *db = NULL;
 144
 145     if (!name_type_ok(context, config, principal))
 146         return HDB_ERR_NOENTRY;
 147
 148     flags |= HDB_F_DECRYPT;
 149     if (kvno_ptr != NULL && *kvno_ptr != 0) {
 150         kvno = *kvno_ptr;
 151         flags |= HDB_F_KVNO_SPECIFIED;
 152     } else {
 153         flags |= HDB_F_ALL_KVNOS;
 154     }
 155
 156     ent = calloc(1, sizeof (*ent));
 157     if (ent == NULL)
 158         return krb5_enomem(context);
 159
 160     if (principal->name.name_type == KRB5_NT_ENTERPRISE_PRINCIPAL) {
 161         if (principal->name.name_string.len != 1) {
 162             ret = KRB5_PARSE_MALFORMED;
 163             krb5_set_error_message(context, ret,
 164                                    "malformed request: "
 165                                    "enterprise name with %d name components",
 166                                    principal->name.name_string.len);
 167             goto out;
 168         }
 169         ret = krb5_parse_name(context, principal->name.name_string.val[0],
 170                               &enterprise_principal);
 171         if (ret)
 172             goto out;
 173     }
 174
 175     for (i = 0; i < config->num_db; i++) {
 176         HDB *curdb = config->db[i];
 177
 178         if (db)
 179             *db = curdb;
 180
 181         ret = curdb->hdb_open(context, curdb, O_RDONLY, 0);
 182         if (ret) {
 183             const char *msg = krb5_get_error_message(context, ret);
 184             kdc_log(context, config, 0, "Failed to open database: %s", msg);
 185             krb5_free_error_message(context, msg);
 186             continue;
 187         }
 188
 189         princ = principal;
 190         if (!(curdb->hdb_capability_flags & HDB_CAP_F_HANDLE_ENTERPRISE_PRINCIPAL) && enterprise_principal)
 191             princ = enterprise_principal;
 192
 193         ret = hdb_fetch_kvno(context, curdb, princ, flags, 0, 0, kvno, ent);
 194         curdb->hdb_close(context, curdb);
 195
 196         if (ret == HDB_ERR_NOENTRY)
 197             continue; /* Check the other databases */
 198
 199         /*
 200          * This is really important, because errors like
 201          * HDB_ERR_NOT_FOUND_HERE (used to indicate to Samba that
 202          * the RODC on which this code is running does not have
 203          * the key we need, and so a proxy to the KDC is required)
 204          * have specific meaning, and need to be propogated up.
 205          */
 206         break;
 207     }
 208
 209     switch (ret) {
 210     case HDB_ERR_WRONG_REALM:
 211     case 0:
 212         /*
 213          * the ent->entry.principal just contains hints for the client
 214          * to retry. This is important for enterprise principal routing
 215          * between trusts.
 216          */
 217         *h = ent;
 218         ent = NULL;
 219         break;
 220
 221     case HDB_ERR_NOENTRY:
 222         if (db)
 223             *db = NULL;
 224         if ((flags & HDB_F_GET_CLIENT) && (flags & HDB_F_SYNTHETIC_OK) &&
 225             config->synthetic_clients) {
 226             ret = synthesize_client(context, config, principal, db, h);
 227             if (ret) {
 228                 krb5_set_error_message(context, ret, "could not synthesize "
 229                                        "HDB client principal entry");
 230                 ret = HDB_ERR_NOENTRY;
 231                 krb5_prepend_error_message(context, ret, "no such entry found in hdb");
 232             }
 233         } else {
 234             krb5_set_error_message(context, ret, "no such entry found in hdb");
 235         }
 236         break;
 237
 238     default:
 239         if (db)
 240             *db = NULL;
 241         break;
 242     }
 243
 244 out:
 245     krb5_free_principal(context, enterprise_principal);
 246     free(ent);
 247     return ret;
 248 }
 249
 250 KDC_LIB_FUNCTION void KDC_LIB_CALL
 251 _kdc_free_ent(krb5_context context, HDB *db, hdb_entry *ent)
 252 {
 253     hdb_free_entry (context, db, ent);
 254     free (ent);
 255 }
 256
 257 /*
 258  * Use the order list of preferred encryption types and sort the
 259  * available keys and return the most preferred key.
 260  */
 261
 262 krb5_error_code
 263 _kdc_get_preferred_key(krb5_context context,
 264                        krb5_kdc_configuration *config,
 265                        hdb_entry *h,
 266                        const char *name,
 267                        krb5_enctype *enctype,
 268                        Key **key)
 269 {
 270     krb5_error_code ret;
 271     int i;
 272
 273     if (config->use_strongest_server_key) {
 274         const krb5_enctype *p = krb5_kerberos_enctypes(context);
 275
 276         for (i = 0; p[i] != ETYPE_NULL; i++) {
 277             if (krb5_enctype_valid(context, p[i]) != 0 &&
 278                 !_kdc_is_weak_exception(h->principal, p[i]))
 279                 continue;
 280             ret = hdb_enctype2key(context, h, NULL, p[i], key);
 281             if (ret != 0)
 282                 continue;
 283             if (enctype != NULL)
 284                 *enctype = p[i];
 285             return 0;
 286         }
 287     } else {
 288         *key = NULL;
 289
 290         for (i = 0; i < h->keys.len; i++) {
 291             if (krb5_enctype_valid(context, h->keys.val[i].key.keytype) != 0 &&
 292                 !_kdc_is_weak_exception(h->principal, h->keys.val[i].key.keytype))
 293                 continue;
 294             ret = hdb_enctype2key(context, h, NULL,
 295                                   h->keys.val[i].key.keytype, key);
 296             if (ret != 0)
 297                 continue;
 298             if (enctype != NULL)
 299                 *enctype = (*key)->key.keytype;
 300             return 0;
 301         }
 302     }
 303
 304     krb5_set_error_message(context, ret = KRB5KDC_ERR_ETYPE_NOSUPP,
 305                            "No valid kerberos key found for %s", name);
 306     return ret;
 307 }
 308
 309 krb5_error_code
 310 _kdc_verify_checksum(krb5_context context,
 311                      krb5_crypto crypto,
 312                      krb5_key_usage usage,
 313                      const krb5_data *data,
 314                      Checksum *cksum)
 315 {
 316     krb5_error_code ret;
 317
 318     ret = krb5_verify_checksum(context, crypto, usage,
 319                                data->data, data->length,
 320                                cksum);
 321     if (ret == KRB5_PROG_SUMTYPE_NOSUPP)
 322         ret = KRB5KDC_ERR_SUMTYPE_NOSUPP;
 323
 324     return ret;
 325 }
 326
 327 /*
 328  * Returns TRUE if a PAC should be included in ticket authorization data.
 329  *
 330  * Per [MS-KILE] 3.3.5.3, PACs are always included for TGTs; for service
 331  * tickets, policy is governed by whether the client explicitly requested
 332  * a PAC be omitted when requesting a TGT, or if the no-auth-data-reqd
 333  * flag is set on the service principal entry.
 334  *
 335  * However, when issuing a cross-realm TGT to an AD realm our PAC might not
 336  * interoperate correctly.  Therefore we honor the no-auth-data-reqd HDB entry
 337  * flag on cross-realm TGTs.
 338  */
 339
 340 krb5_boolean
 341 _kdc_include_pac_p(astgs_request_t r)
 342 {
 343     return TRUE;
 344 }
 345
 346 /*
 347  * Notify the HDB backend and KDC plugin of the audited event.
 348  */
 349
 350 krb5_error_code
 351 _kdc_audit_request(astgs_request_t r)
 352 {
 353     krb5_error_code ret;
 354     struct HDB *hdb;
 355
 356     ret = _kdc_plugin_audit(r);
 357     if (ret == 0 &&
 358         (hdb = r->clientdb ? r->clientdb : r->config->db[0]) &&
 359         hdb->hdb_audit)
 360         ret = hdb->hdb_audit(r->context, hdb, r->client, (hdb_request_t)r);
 361
 362     return ret;
 363 }